Tweak particles to have more nuanced colors

src/refresh/vkpt/color.h

@@ -0,0 +1,44 @@
+/*
+Copyright (C) 2019, NVIDIA CORPORATION. All rights reserved.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#ifndef COLOR_H_
+#define COLOR_H_
+
+static inline float decode_srgb(byte pix)
+{
+	float x = (float)pix / 255.f;
+
+	if (x < 0.04045f)
+		return x / 12.92f;
+
+	return powf((x + 0.055f) / 1.055f, 2.4f);
+}
+
+static inline byte encode_srgb(float x)
+{
+    if (x <= 0.0031308f)
+        x *= 12.92f;
+    else
+        x = 1.055f * powf(x, 1.f / 2.4f) - 0.055f;
+
+    x = max(0.f, min(1.f, x));
+
+    return (byte)roundf(x * 255.f);
+}
+
+#endif // COLOR_H_

src/refresh/vkpt/shader/global_ubo.h

@@ -89,7 +89,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 	UBO_CVAR_DO(pt_metallic_override, -1) /* overrides metallic parameter of all materials if non-negative, [0..1] */ \
 	UBO_CVAR_DO(pt_ndf_trim, 0.9) /* trim factor for GGX NDF sampling (0..1] */ \
 	UBO_CVAR_DO(pt_num_bounce_rays, 1) /* number of bounce rays, valid values are 0 (disabled), 0.5 (half-res diffuse), 1 (full-res diffuse + specular), 2 (two bounces) */ \
-	UBO_CVAR_DO(pt_particle_softness, 1.0) /* particle softness */ \
+	UBO_CVAR_DO(pt_particle_softness, 0.7) /* particle softness */ \
+	UBO_CVAR_DO(pt_particle_brightness, 100) /* particle brightness */ \
 	UBO_CVAR_DO(pt_reflect_refract, 2) /* number of reflection or refraction bounces: 0, 1 or 2 */ \
 	UBO_CVAR_DO(pt_roughness_override, -1) /* overrides roughness of all materials if non-negative, [0..1] */ \
 	UBO_CVAR_DO(pt_specular_anti_flicker, 2) /* fade factor for rough reflections of surfaces far away, [0..inf) */ \

src/refresh/vkpt/shader/path_tracer_hit_shaders.h

@@ -95,7 +95,7 @@ vec4 pt_logic_particle(int primitiveID, vec2 bary)
 		color.a *= factor;
 		color.rgb *= color.a;
 
-		color.rgb *= global_ubo.prev_adapted_luminance * 500;
+		color.rgb *= global_ubo.prev_adapted_luminance * global_ubo.pt_particle_brightness;
 
 		return color;
 	}

src/refresh/vkpt/textures.c

@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #include <assert.h>
 
+#include "color.h"
 #include "material.h"
 #include "../stb/stb_image.h"
 #include "../stb/stb_image_resize.h"
@@ -518,28 +519,6 @@ IMG_Load
 ================
 */
 
-static inline float decode_srgb(byte pix)
-{
-	float x = (float)pix / 255.f;
-
-	if (x < 0.04045f)
-		return x / 12.92f;
-
-	return powf((x + 0.055f) / 1.055f, 2.4f);
-}
-
-static inline byte encode_srgb(float x)
-{
-    if (x <= 0.0031308f)
-        x *= 12.92f;
-    else
-        x = 1.055f * powf(x, 1.f / 2.4f) - 0.055f;
-
-    x = max(0.f, min(1.f, x));
-
-    return (byte)roundf(x * 255.f);
-}
-
 struct filterscratch_s
 {
 	int num_comps;

src/refresh/vkpt/transparency.c

@@ -20,6 +20,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "shared/shared.h"
 #include "vkpt.h"
 #include "vk_util.h"
+#include "color.h"
 #include "conversion.h"
 
 #define TR_PARTICLE_MAX_NUM    MAX_PARTICLES
@@ -99,12 +100,12 @@ void cast_u32_to_f32_color(int color_index, const color_t* pcolor, float* color_
 		color.u32 = d_8to24table[color_index & 0xff];
 
 	for (int i = 0; i < 3; i++)
-		color_f32[i] = hdr_factor * ((float)color.u8[i] / 255.0);
+		color_f32[i] = hdr_factor * decode_srgb(color.u8[i]);
 }
 
 bool initialize_transparency()
 {
-	cvar_pt_particle_size = Cvar_Get("pt_particle_size", "0.35", 0);
+	cvar_pt_particle_size = Cvar_Get("pt_particle_size", "0.5", 0);
 	cvar_pt_beam_width = Cvar_Get("pt_beam_width", "1.0", 0);
 	cvar_pt_beam_lights = Cvar_Get("pt_beam_lights", "1.0", 0);